U.S. patent number 6,571,531 [Application Number 09/824,356] was granted by the patent office on 2003-06-03 for strap detector assembly.
This patent grant is currently assigned to Illinois Tool Works, Inc.. Invention is credited to Calvin E. Kasel.
United States Patent |
6,571,531 |
Kasel |
June 3, 2003 |
Strap detector assembly
Abstract
A strap detector is used with an automatic strapping machine.
The strap detector includes a strap detector mounting bracket
mounted to the automatic strapping machine, and a pivot block
attached to the mounting bracket. The pivot block has an aperture
formed therein. A shaft is positioned in the pivot block aperture,
and a finger is mounted to a free end of the shaft. A guide block
is positioned along the shaft and spaced from the free end, and a
sensor is operatively coupled to the detector mounting bracket
proximal the guide block. The finger is engaged by sealed strapping
material and, when the strapping material is properly sealed,
movement of the strapping head away from the articles moves the
guide block into a position to change a state of the sensor.
Inventors: |
Kasel; Calvin E. (Wauconda,
IL) |
Assignee: |
Illinois Tool Works, Inc.
(Glenview, IL)
|
Family
ID: |
25241179 |
Appl.
No.: |
09/824,356 |
Filed: |
April 2, 2001 |
Current U.S.
Class: |
53/75; 100/26;
100/4; 156/363; 156/475; 53/582 |
Current CPC
Class: |
B65B
13/18 (20130101); B65B 57/04 (20130101); B65B
57/18 (20130101) |
Current International
Class: |
B65B
13/18 (20060101); B65B 57/02 (20060101); B65B
57/00 (20060101); B65B 57/04 (20060101); B65B
57/18 (20060101); B65B 057/08 (); B65B
011/08 () |
Field of
Search: |
;53/582,589,53,64,508,75
;100/4,26 ;156/64,352,363,379,475 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gerrity; Stephen F.
Assistant Examiner: Durand; Paul
Attorney, Agent or Firm: Croll; Mark W. Breh; Donald J.
Welsh & Katz, Ltd.
Claims
What is claimed is:
1. A swap detector for use with an automatic strapping machine
configured to strap articles together by conveying strapping
material into a first end of chute, the strapping material exiting
the chute at a second end and being sealed to itself at a strapping
head, the strapping head moving away from the articles after
forming a seal and toward the articles to form the seal, the strap
detector being configured to determine whether the strapping
material is positioned and sealed around the articles, the strap
detector comprising: a strap detector mounting bracket mounted to
the automatic strapping machine, the strap detector mounting
bracket having a slot having an angled portion relative to a
direction of movement of the strapping head; a pivot block mounted
to the mounting bracket, the pivot block having an aperture formed
therein; a shaft positioned in the pivot block aperture; a finger
mounted to the shaft at a free end; a sensed element positioned
along the shaft spaced from the free end, the sensed element
including a guide thereon configured to cooperate with the slot
during movement of the sensed element to pivot the finger
transverse to the direction of movement of the strapping head; and
a sensor operatively coupled to the detector mounting bracket at a
predetermined position relative to the sensed element, the sensor
having a first state and a second state and being changeable
therebetween,
wherein when the finger engages strapping material positioned and
sealed around the articles, movement of the strapping head away
from the articles moves the sensed element and the sensor from the
predetermined position relative to one another to change the state
of the sensor from the first state to the second state.
2. The strap detector in accordance with claim 1 wherein the sensed
element is a guide block.
3. The strap detector in accordance with claim 1 further including
a sensor support bracket mounted to the detector mounting bracket,
wherein the sensor is operatively coupled to the detector mounting
bracket by the sensor support bracket.
4. The strap detector in accordance with claim 1, wherein the
sensed element is formed as a guide block and wherein movement of
the guide block along the slot pivots the finger transverse to the
direction of movement of the strapping head.
5. The strap detector in accordance with claim 1 wherein the guide
is a bearing.
6. The strap detector in accordance with claim 1 wherein the sensor
is a proximity sensor.
7. The strap detector in accordance with claim 1 further including
a biasing element positioned along the shaft to bias the sensor and
sensed element to the predetermined position.
8. An automatic strapping machine configured to strap articles
together by conveying strapping material into a first end of a
chute, the strapping material exiting the chute at a second end and
being sealed to itself, the automatic strapping machine comprising:
a strapping head, the strapping head moving toward and away from
the articles, the strapping moving toward the articles to convey
the strapping material into the first end of the chute and to seal
the strapping material to itself, and moving away from the articles
after sealing the strapping material to itself; and a strap
detector, the strap detector configured to determine whether the
strapping material is positioned and sealed around the articles,
the strap detector including a strap detector mounting bracket
mounted to the strapping head, the strap detector mounting bracket
having a cam groove formed therein, the cam groove being formed as
a slot having an angled portion relative to a direction of movement
of the strapping head, a pivot block mounted to the mounting
bracket, the pivot block having an aperture formed therein, a shaft
positioned in the pivot block aperture, a finger mounted to the
shaft at a free end, a sensed element positioned along the shaft
spaced from the free end, the sensed element including a bearing
thereon, the bearing being configured to cooperate with the cam
groove during movement of the sensed element along the slot,
movement of the sensed element pivoting the finger transverse to
the direction of movement of the strapping head, a sensor support
bracket mounted to the detector mounting bracket, the support
bracket having an elongated slot formed therein, a proximity sensor
mounted to the elongated slot in the sensor support bracket at a
predetermined position relative to the sensed element, the
proximity sensor having a first state and a second state and being
changeable therebetween, and a biasing element positioned along the
shaft to bias the sensor and sensed element to the predetermined
position, wherein when the finger engages strapping material
positioned and sealed around the articles, movement of the
strapping head away from the articles moves the sensed element and
the sensor from the predetermined position relative to one another
to change the state of the sensor from the first state to the
second state.
9. The automatic strapping machine in accordance with claim 8
wherein the sensed element is a guide block.
10. The automatic strapping machine in accordance with claim 8
wherein the strap detector mounting bracket is mounted to the
strapping head.
11. The automatic strapping machine in accordance with claim 8
further including a notification device, wherein the notification
device is actuated if the sensor state does not change after the
strapping head moves away from the articles.
12. The automatic strapping machine in accordance with claim 11
wherein the notification device disables the strapping machine when
actuated.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a strap detector assembly for
automatic strapping machines. More particularly, the present
invention relates to a detector for determining whether strapping
material is properly positioned around and sealed to a load.
Strapping machines are typically used to strap articles or a load
together. There are two principal types of strapping machines known
in the art: (1) manual strapping machines; and (2) automatic
strapping machines.
One type of automatic strapping machine includes a frame-like
support for the overall machine, a strapping head, a chute around
which the strap is fed and one or more dispensers for dispensing
the strap material to the strapping head.
The strapping head moves toward the load, pulls the strap material
from the dispensers, and conveys the strapping material to a first
end of the chute until a leading portion of the strap returns to
the strapping head. At the strapping head, the leading portion or
leading end is gripped and the trailing portion or end of the strap
is retracted and tensioned to provide an appropriate compression on
the strapped load. The strap is then sealed to itself in an
overlapping manner, the trailing end portion is severed and the
load removed from the machine. The strapping head moves away from
the load after each strapping operation has been completed. This
process can be repeated for an extended period of time with very
little human intervention.
However, occasionally, while the automatic strapping machine is
operating without human intervention, the strapping material is
improperly sealed around the load. In these circumstances, an
improperly secured load results which can result in load tipping
and spillage. This can result in the loss of load and labor
resources. It would be impractical in terms of both man-hours and
strapping operation time to require an employee to supervise
automatic strapping machine operations.
Accordingly, there continues to be a need for an automatic
strapping machine, or a device to be used with an automatic
strapping machine, that ensures that strapping material is properly
sealed around a load, thus facilitating a properly secured
load.
SUMMARY OF THE INVENTION
The present invention relates to an automatic strapping machine
configured to strap articles together by conveying strapping
material into a first end of a chute. The strapping material exits
the chute at a second end and is sealed to itself at a strapping
head. The strapping head moves away from the articles after forming
a seal and toward the articles to form the seal.
The automatic strapping machine comprises the strapping head and a
strap detector mounting bracket mounted to the automatic strapping
machine. In one embodiment, the strap detector mounting bracket can
be mounted to the strapping head.
A pivot block can be attached to the mounting bracket, and the
pivot block can have an aperture formed therein. A shaft can be
positioned in the pivot block aperture, and a finger can be mounted
to the shaft at a free end. A sensed element, such as a guide
block, can be positioned along the shaft spaced from the free
end.
A proximity sensor can be operatively coupled to the detector
mounting bracket proximal the guide block. The finger can be
engaged by sealed strapping material during a strapping operation
and, if the strapping material is properly sealed to itself,
movement of the strapping head away from the articles moves the
guide block into a position to change a state of the sensor.
The automatic strapping machine can further include a notification
device. The notification device can be actuated if the sensor state
does not change after the strapping head moves away from the
articles. Preferably, the notification device disables the
strapping machine when it is actuated.
The automatic strapping machine can also include a biasing element
positioned along the shaft, and positioned between the guide block
and the pivot block. In one embodiment, the biasing element is a
spring.
In one embodiment, the sensor is operatively coupled to the
detector mounting bracket by the sensor support bracket.
Preferably, an elongated slot is formed within the sensor support
bracket and the sensor is connected to the sensor support at the
elongated slot. Thus, the elongated slot allows for sensor position
adjustment.
The guide block can include a guide attached to a bottom surface of
the guide block and a cam groove can be formed within the detector
mounting bracket. The cam groove and guide can be configured to
cooperate with one another. The guide can be a bearing, and the
sensor can be a proximity sensor.
Other features and advantages of the present invention will be
apparent from the following detailed description, the accompanying
drawings, and the appended claims.
BRIEF DESCRIPTION OF THE FIGURES
The benefits and advantages of the present invention will become
more readily apparent to those of ordinary skill in the art after
reviewing the following detailed description and accompanying
drawings, wherein:
FIG. 1 is a top view of a detector assembly in the home state,
embodying principles of the present invention;
FIG. 2 is a side view of the detector assembly of FIG. 1;
FIG. 3 is a front schematic view of an automatic strapping machine
with the detector assembly of FIG. 1 attached thereto; and,
FIGS. 3a-c demonstrate the sequence of operations of the strap
detector of FIG. 1 as it interacts with a package to be
wrapped.
FIG. 4 is a top view of the detector assembly of FIG. 1 in the
secure state.
DETAILED DESCRIPTION OF THE INVENTION
While the invention is susceptible to various embodiments, there is
shown in the drawings and will hereinafter be described specific
embodiments with the understanding that the present disclosure is
to be considered an exemplification of the invention and is not
intended to limit the invention to the specific embodiments
illustrated and described.
It is to be further understood that the title of this section of
the specification, namely, "Detailed Description of the Invention,"
relates to a requirement of the United States Patent and Trademark
Office, and does not imply, nor should be inferred to limit the
subject matter disclosed herein and the scope of the present
invention.
Referring to the figures, and in particular to FIGS. 1 and 2, there
is shown an exemplary strap detector assembly 2 for automatic
strapping machines embodying the principles of the present
invention. The detector assembly 2 includes a pivot block 4 with a
shaft aperture 6 formed therein. The pivot block 4 is mounted to a
strap detector mounting bracket 8 and is configured to pivot about
the mounting bracket 8. A shaft 10, having a finger 12 mounted to
the shaft 10 at a free end 14, is positioned within the shaft
aperture 6. A sensed element, such as the illustrated guide block
16, which is spaced from the finger 12, is also attached to the
shaft 10. Preferably, as shown in FIGS. 1-2, the guide block 16 is
attached by connectors 18 that allow for the guide block 16
position to be adjusted along the shaft 10.
A guide 20, such as a pin or bearing, is connected to a bottom
surface of the guide block 16, and a cam groove 22 is formed within
the strap detector mounting bracket 8. The guide 20 and cam groove
22 are configured to cooperate with one another so the guide 20 can
move along a path P defined by the cam groove 22. Preferably, a
biasing element 24, such as, for example, a spring, is positioned
along the shaft 10, and positioned between the guide and pivot
blocks 16, 4.
The illustrated detector assembly 2 also includes a sensor support
bracket 26 attached to the pivot block 4, and a sensing element 28,
such as a proximity sensor, connected to the sensor support bracket
26. In the illustrated embodiment, the sensing element 28 is
positioned proximal the guide block 16 while in a home state
position (FIG. 1). Preferably, an elongated slot 30 is formed
within the sensor support bracket 26 to allow for lateral
adjustment (toward and away from the pivot block 4) of the sensing
element 28 position along the sensor support bracket 26.
The illustrated detector assembly 2 is configured for use with an
automatic strapping machine 32, such as the MCD 510/BCU-3 automatic
strapping machine manufactured by ITW-Signode, of Glenview, Ill.,
which is schematically shown in FIG. 3. The automatic strapping
machine 32 includes a strapping machine body 34, a strapping head
36, a chute 38, and the detector assembly 2. A strapping material
dispenser (not shown) feeds strapping material to the machine 32
for strapping around a load L. Preferably, the illustrated detector
assembly 2 of FIGS. 1-2 is mounted to the strapping head 36 of the
automatic strapping machine 32.
As shown in FIG. 3, the strapping head 36 advances toward the load
along a rail 40 before it begins a strapping operation. As shown in
FIG. 1, at this point, the illustrated detector assembly 2 is in a
home state. The strapping head 36 conveys a leading portion of
strapping material to a first end 42 of the chute 38 and receives
the leading portion of strapping material from a second end 44 of
the chute 38. The strapping material is then gripped, retracted,
sealed to itself, and cut to strap the load L together.
Occasionally, a faulty seal is formed in the strap around the load
L because the strapping material was improperly gripped, retracted
or sealed for example. The strapping may also have broken during
one strapping operation. This inevitably results in load tippage or
spillage, and because each load can include thousands of articles,
each tip or spill can result in the loss of articles and employee
clean up time.
Typically, several automatic strapping machines operate
simultaneous at factory and/or packaging sites. Therefore, although
human supervision of strapping operations may alleviate the
spillage problem, such a solution is economically and commercially
impractical because of the numerous automatic strapping machines
that would require supervision.
The present invention allows for effective seal integrity
examination without the need for constant human supervision.
Pursuant to the present invention, a detector assembly 2 employing
a sensing element 28 that is used to check for faulty seals is used
with automatic strapping machines.
During the strapping operation described above, when the head 36
moves to the load L to begin one strapping operation, the finger 12
is positioned adjacent the load L along the strap path, and is
essentially strapped to the load. As shown in FIG. 4, after a
strapping operation is complete, the finger 12 remains in position
"under" the strap, and the strapping head 36 moves away from the
load. When the strapping head 36 moves away from the load L, if a
proper strapping operation has been performed, the detector
assembly 2 temporarily changes from a home state position to a
secure state position. In the secure state (FIG. 4), the finger 12
remains secured to the load L by the strapping material while the
strapping head 36 moves away (as indicated by the arrow at 48),
causing the guide 20 to move the guide block 16 along the cam
groove 22. Preferably, as shown in FIG. 4, the cam groove 22 is at
an angle relative to movement 48 of the head 34, causing the finger
12 and shaft 10 to pivot about the pivot block 4, as indicated by
the arrow at 50. This causes the finger 12 to move out and away
from the strapping materials. As seen in FIG. 4, as the shaft 10
and finger 12 pivot, the finger 12 "slips" past the strap S, so
that the strap S remains secured around the load L. If, however, an
improper strapping operation was performed, the detector assembly
will simply move away from the load while still in the home state
position.
As shown in FIG. 1, the guide block 4 is initially proximal to the
proximity sensor 28 in the home state position. FIG. 4 shows the
secure state in which the guide block 16 moves away from (e.g., is
spaced from) the proximity sensor 28. When the proximity sensor 28
detects movement of the guide block 16 away from the sensor 28, a
change in the state of the sensor 28 occurs. This, in the
illustrated embodiment, indicates that a proper strapping operation
has been performed, i.e. the guide block 16 is spaced from the
proximity sensor 28 in the secure state position. When there is no
change in the state of the sensor 28, this indicates that the guide
block 16 has not changed position after the strapping head 36 has
moved away from the load, which is indicative that a faulty
operation has been performed, i.e. the guide block 16 stays
proximal to the proximity sensor 28 in the home position.
Those skilled in the art will recognize the various types of
proximity sensors that can be used. In a present embodiment, an
inductive proximity sensor is used, which is commercially available
from Turck, Inc. of Minneapolis, Minn. Other types of sensors,
including other electronic, as well as electro-mechanical types
detectors (e.g., limit switches and the like), their general design
and use, will be recognized and appreciated by those skilled in the
art. All such sensors are within the scope and spirit of the
present invention.
Typically, if a proper strapping operation occurred, after the
strapping head 36 has moved away from the load, the spring 24
returns the guide block 16 to a home state position, and the
proximity sensor 28 resets.
If the proximity sensor 28 determines an improper strapping
operation has been detected, the proximity sensor 28 can desirably
actuate a notification device 46, such as, for example, an audible
and/or visual alarm. Preferably, when the notification device 46 is
actuated because of a faulty strapping operation, it causes the
automatic strapping machine 32 to be temporarily disabled in order
to prevent further faulty strapping operations. An operator can
then attend to the strapping machine to resolve any problem.
In the present disclosure, the words "a" or "an" are to be taken to
include both the singular and the plural. Conversely, any reference
to plural items shall, where appropriate, include the singular.
From the foregoing it will be observed that numerous modification
and variations can be effectuated without departing from the true
spirit and scope of the novel concepts of the invention. It is to
be understood that no limitation with respect to the specific
embodiment illustrated is intended or should be inferred. The
disclosure is intended to cover by the appended claims all such
modifications as fall within the scope of the claims.
* * * * *